Multicore optical fibers and methods of manufacturing the same

ABSTRACT

A multicore optical fiber with a reference section having a material defining a marked multicore glass optical fiber. The multicore fibers can be in groupings, for example, the groupings can be in the form of one of an optical fiber ribbon covered by a matrix, and a tight buffered cable. Fiber optic connectors can be assembled to the multicore optical fiber at either or both ends, and the colored portion can be associated with the optical fiber connector aligning the optical core elements with the optical connectors. The assembly can have at least one transceiver device with a transmit port and a receive port defining a two-way communication channel. Further aspects describe methods of manufacturing multicore fibers including application of curable coatings and reference sections.

This application is a divisional of U.S. application Ser. No. 14/136,434filed on Dec. 20, 2013 which claims the benefit of priority to U.S.Provisional Application Ser. No. 61/907,755 filed on Nov. 22, 2013, bothapplications being incorporated herein by reference in their entireties.

BACKGROUND

Field

The present disclosure generally relates to optical fibers and, morespecifically, to multicore optical fibers.

Technical Background

Optical fiber is the leading alternative to traditional materials usedfor data signal communication such as copper wiring. Optical fiber isnow widely utilized in a variety of electronic devices and systems tofacilitate the high-speed communication of voice, video, and datasignals at high bandwidths. However, as the speed and bandwidth of theelectronic systems increases, there is a corresponding need to increasethe speed of optical interconnects which interconnect components of thesystem. One solution to increase the speed of optical interconnects isto increase the fiber density of the optical interconnects. However,increasing the number of individual fibers in an optical interconnectincreases the overall size and cost of the optical interconnect. Toavoid the increased fiber count, multicore optical fibers (“MCFs”) havebeen developed. MCFs contain optical core elements contained in a singlefiber. The core elements are designed for, for example, the transmissionand receiving of data, and can be arranged as transmit and receive(Tx/Rx) pairs. Such MCFs may be used in data networks to enable highspeed Tx/Rx transmission of data between system components such astransceivers, processors, servers, and storage devices. For connectionand termination in the networks, connectors are attached to the MCFs.For correct Tx/Rx optical transport and connections to be manufactured,it is important for the operators to know the orientation of the opticalfibers when the connectors are terminated to the MCFs.

SUMMARY

According to embodiments of the present disclosure, a multicore opticalfiber for use with, for example, at least one transceiver device, forexample, an opto/electronic comprises optical core elements, the opticalcore elements comprising an array of at least two optical core elementscontained within a common outer cladding, the common outer claddingbeing at least partially surrounded by a coating layer, the respectivecenters of the optical core elements being aligned along a firstreference line and being capable of transmitting data, and the multicoreoptical fiber comprising at least one colored portion defining a markedmulticore fiber. The colored portion can be selected from a UV lightcurable resin material and an ink material and combinations thereof, andthe coating layer can include a color and the least one colored portioncan include a relatively distinct color compared to the coating layercolor. The colored portion can extend along the multicore optical fiberand can be in the form of one of a continuous line, an intermittentline, a ring, or combinations thereof. In addition, the colored portioncan be one of a co-extruded layer adjacent the coating layer and amaterial applied to an outer surface of the coating layer andcombinations thereof. The colored portion is disposed generally inalignment with the reference line, or it can be disposed in otherpositions, for example, generally above the reference line.

Marked multicore fibers can be arranged in groupings. For example, thegroupings can be in the form of one of an optical fiber ribbon coveredby a matrix, and a loosely disposed group of marked multicore opticalfibers, and combinations thereof. Moreover, a cable jacket can surroundat least one marked multicore optical fiber and at least one strengthmember. In addition, the marked multicore optical fiber can be part ofan assembly comprising at least one opto/electronic transceiver systemwith at least one transmit port and at least one receive port definingat least one two-way communication channel moreover, at least one fiberoptic connector can be assembled to the marked multicore optical fiber,and the colored portion can be associated with the optical fiberconnector aligning the optical core elements indicating alignment of theoptical elements with the optical connector.

Further embodiments describe methods of manufacturing multicore fibersand others aspects according to the foregoing. An exemplary methodcomprises the steps of translating an uncoated multicore optical fiberbetween an energy source and a detector, directing a beam of the energysource so that it at least partially impinges upon the multicore opticalfiber causing an image to be detected by the detector, and the detectorsending output to a controller, the controller determining theorientation of at least some of the core elements in the multicoreoptical fiber, and controlling a spinning or traction device and therebyadjusting the orientation of the multicore optical fiber in relation toits optical core elements and a coating die, passing the multicoreoptical fiber through the coating die and applying a material to themulticore optical fiber thus defining a coating portion, and applying amaterial in the form of a colored portion being visually distinct fromthe coating portion.

Variations of the foregoing methods are included as embodiments of thedisclosure. For example, the step of detecting the image of at leastsome of the core elements can include at least partial absorption of theenergy by at least one dopant which is respectively part of the opticalcore elements, and the dopant can be, for example, a germanium dopant.Other dopants can be used in accordance with the disclosure which willpotentially result in alternative absorption and transmittancecharacteristics. Alternatively, the step of energy absorption can causefluorescence and the step of determining the orientation of at leastsome of the core elements can involve imaging of the fluorescence. Inyet another alternative, the step of energy absorption can cause indexof refraction differences and the step of detection of the image canthus be based upon interferometry.

As to the manufacturing line embodiments of the disclosure, determiningthe orientation of at least some of the core elements in the multicoreoptical fiber can include programming at least one characteristicabsorption wavelength band of the dopant and cladding in an imagingsystem. In other embodiments, applying a material to the coating portioncan include a colored portion visually distinct from the coating portionincluding one of co-extruding the colored portion and of applying an inkto the outer surface of the coating portion, and combinations thereof.In yet further embodiments of the disclosure, applying the coloredportion can comprise one of forming the colored portion with one or morestripes, dashes, rings, or a series of rings and stripes thereon, andcombinations thereof. As to exemplary groupings of marked multicoreoptical fibers, the manufacturing method can comprise translating atleast two multicore optical fibers, aligning the colored portionsrespectively of the multicore optical fibers, coating the multicoreoptical fibers with a matrix material so they are contained in thematrix, curing the matrix material, and optionally applying a referencesection to the matrix.

As alternative processes of the embodiments disclosed herein,translating the multicore optical fibers can include drawing an uncoatedmulticore optical fiber from a draw tower or supplying a multicore fiberwith a colored portion from a reel. As to the draw tower alternative,the step of coating the multicore optical fiber can occur after coolingof the multicore optical fiber. Moreover, determining the core elementorientation can occur prior to the coating application step and caninclude controlling the traction device prior to application of thecoating. Furthermore, the steps of applying the colored portion can beone of various embodiments for example: directly applying the coloredportion to the glass after a cooling step but prior to the coatingapplication step, directly applying the colored portion to the coatingafter the coating step but before a curing step of the coating, directlyapplying the colored portion to the coating after a curing step of thecoating, and combinations thereof

Additional features and advantages of the embodiments described hereinwill be set forth in the detailed description which follows, and in partwill be readily apparent to those skilled in the art from thatdescription or recognized by practicing the embodiments describedherein, including the detailed description which follows, the claims, aswell as the appended drawings. Moreover, it is to be understood thatboth the foregoing general description and the following detaileddescription describe various embodiments and are intended to provide anoverview or framework for understanding the nature and character of theclaimed subject matter. The accompanying drawings are included toprovide a further understanding of the various embodiments, and areincorporated into and constitute a part of this specification. Thedrawings illustrate the various embodiments described herein, andtogether with the description serve to explain the principles andoperations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings are made a part of this disclosure:

FIG. 1 schematically depicts one embodiment of a multicore optical fiberaccording to one or more embodiments shown and described herein beforeapplication of a colored portion;

FIG. 2 schematically depicts an embodiment of a marked multicore opticalfiber according to one or more embodiments shown and described hereinwith at least one colored portion, for example, disposed along a commonaxis of the core elements;

FIG. 3 schematically depicts another manufacturing process according toone or more embodiments shown and described herein for making the markedmulticore fiber;

FIG. 4 schematically depicts an exemplary manufacturing processaccording to one or more embodiments shown and described herein formaking the marked multicore fiber;

FIG. 5 schematically depicts a multicore optical fiber according to oneor more embodiments shown and described herein with at least one energybeam transiting across the fiber adjacent some portions of at least onerow of core elements;

FIG. 6 schematically depicts a multicore optical fiber according to oneor more embodiments shown and described herein with the at least oneenergy beam being intercepted by at least some portions of a one row ofcore elements;

FIG. 7 schematically depicts transmission percent as a function ofwavelength for glass materials according to one or more embodimentsshown and described herein;

FIG. 8 schematically depicts an embodiment of marked multicore opticalfibers implemented in an optical fiber ribbon according to one or moreembodiments shown and described herein;

FIG. 9 schematically depicts another manufacturing process according toone or more embodiments shown and described herein for making the markedmulticore fiber;

FIG. 10 schematically depicts another embodiment of a cable with atleast one marked multicore optical fiber therein according to one ormore embodiments shown and described herein with at least one coloredportion, for example, perpendicularly disposed in relation to the commonaxis of the core elements;

FIG. 11 schematically depicts another embodiment of a multicore opticalfiber according to one or more embodiments shown and described hereinwith an exemplary Tx/Rx capability illustrated;

FIG. 12 schematically depicts another embodiment of a multicore opticalfiber according to one or more embodiments shown and described hereinwith an exemplary Tx/Rx interface with optical connectors illustrated;and

FIG. 13 schematically depicts another embodiment of a multicore opticalfiber according to one or more embodiments shown and described hereinwith an exemplary interface with a keyed optical connector illustrated

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of multicoreoptical fibers, examples of which are illustrated in the accompanyingdrawings. Whenever possible, the same reference numerals will be usedthroughout the drawings to refer to the same or like items. Morespecifically, one embodiment of a multicore optical fiber (“MCF”)generally comprises a common outer cladding formed from silica-basedglass and having a cladding index of refraction. At least one opticalcore element, for example, a single mode core element or a multimodecore element, or a combination of such elements, are disposed in thecommon outer cladding. The core element(s) are formed from, for example,silica-based glass with a higher index of refraction than the cladding.A center-to-center spacing between adjacent core elements is forexample, greater than or equal to about 25 μm or less. Variousembodiments of multicore optical fibers and methods for forming the samewill be described in more detail herein with specific reference to theappended drawings. The term “multimode” as used herein refers to a coreelement which supports the propagation of multiple modes of light at thespecified wavelength(s) of, for example, 850 nm to 1550 nm. Multicorefibers are made by exemplary processes disclosed in Corning IncorporatedU.S. Pat. Nos. 6,539,151 and 6,154,594, both of which are respectivelyrelied upon and incorporated by reference herein. The multicore fibersof the embodiments of the disclosure shown, for example in FIGS. 1, 2,and 11, are exemplary and include generally round outer shapes and roundoptical core elements 14, 15, 16, 17. However, the optical core elementscan be other shapes such as rectangular, polygonal, flat, or ellipticalas shown in US Patent Publication No. US 20130177273 A1, which is reliedupon and incorporated by reference herein. In addition, forms ofmulticore fibers other than round, such as rectangular, hexagonal,partly flat and partly rounded forms, and multicore fibers made with aseries of curved surfaces such as are as disclosed U.S. Ser. No.13/485,192, which is relied upon and incorporated by reference herein,can be used with embodiments of the present disclosure.

FIG. 1 depicts a MCF component 10 with optical core elements, forexample, core elements 14, 15, 16, and 17 contained within a commonouter cladding 11 that is covered by a coating system 12 comprising aprimary coating 12 a and a secondary coating 12 b defining a coatingsystem 12. Coating system 12 comprises at least one first referencesection which comprises, a UV light curable resin which is formed of,for example, a first colored material 18. Core elements 14, 15, 16, 17are generally aligned along their respective centers along a line “L1”.The optical core elements 14, 15, 16, 17 can be arranged in a row asshown, for example, in FIGS. 1, 2, and 10. The common outer cladding 11comprises a silica-based glass having a cladding index of refraction. Inone embodiment, optical core elements 14 and 15 are designed tocommunicate data, for example, to transmit data (Tx), and core elements16 and 17 are designed to communicate data, for example, to receive data(Rx) (FIG. 11). A fiber optic connector can be attached to MCF component10 and would connect to, for example, an opto/electronic transceiverdevice (FIGS. 11 and 12). The connector is keyed to align core elements14 and 15 with the device, such as Vertical Cavity Surface EmittingLaser transmitters for Tx purposes, and core elements 16 and 17 are tobe aligned with optical/electronic receiver devices for Rx purposes(FIG. 13). As stated above, MCF components 10 can have two or moresingle mode core elements, two or more multimode core elements, or acombination of single mode and multimode core elements disposed incommon outer cladding 11.

The operator is to align the core elements 14, 15, 16, 17 to theconnectors at each end of the cable using at least one second referencesection. The second reference section comprises, for example, a secondcolored material forming a colored portion 22 (FIG. 2) comprising a UVlight curable resin. With further reference to FIG. 2, MCF component 10includes at least one coating layer, for example, a layer 21, 22 formedof, for example, at least one ink color material as a part of coatingsystem 12 defining a marked MCF 20. For example, the coating layerincludes a coating portion 21 comprising an optical fiber color such asblue or red, and at least one adjacent colored portion 22 comprising arelatively distinct color such as black or white. In exemplaryembodiments, colored portion 22 is disposed in alignment with exemplaryline L1, for example, and colored portion 22 can take the form of acontinuous or intermittent stripe or line of constant or varying width.In other exemplary embodiments described herein, colored portion 22, isdisposed in relation to the first reference section, for example,colored portion 18. Colored portion 22 is adjacent to coating portion 21in the sense that, for example, colored portion 22 is applied to thesurface of, or is alternatively co-extruded with, coating portion 21, asis further described below. The color distinction between portions 20and 21 is observable, during a connector attachment process, by anoperator with or without specialized equipment such as opticalmagnification or illumination equipment. As an alternative toco-extrusion, at least one colored portion 22 can be applied, in anadjacent sense, integrally with the thickness of coating 21, or appliedto a surface of the coating layer with one or more applicators 36 (FIGS.3-4) for example printing devices, for example, ink jet style printers.An applicator can form, for example, a continuous or intermittent linewith dots and dashes and combinations thereof. In exemplary embodiments,the applicator can be located between a coating die and a UV-lightcuring device as further described below (FIG. 4).

In further exemplary embodiments, colored portion 22 can be aligned withan axis of the core elements as shown with reference to exemplary lineL2 (FIG. 10) above core elements 14, 15, 16, 17, for example, at anangle of about 90 degrees relative to line L1. The location andcomposition of colored portion 22, and additional colored portions 22,can be added as desired, and can be disposed at various locationsrelative to, for example, the center of marked MCF 20 to facilitate theoperator's requirements as needed. In other words, the referencesections can be placed at various radial locations, for example, amarked MCF 20 can have at least one colored portion 18 aligned with lineL2 (FIG. 10) and at least one colored portion 22 aligned with line L1(FIG. 2), or both colored portions 18,22 can be aligned with line L2(FIG. 10). The angular precision of colored portion 22 relative toexemplary lines L1 and L2 can be adjusted depending on the requirementsfor the application in which it is used. In general, for the purposes oforienting marked MCF 20 with a connector or to identify the top of afiber in production (FIGS. 11-13), in an exemplary embodiment, theangular accuracy can be on the order of, for example, +/−1 degree ofarc.

FIG. 3 depicts an exemplary glass optical fiber manufacturing process 70such that the first reference section, for example, colored portion 18is disposed on the optical fiber during the fiber drawing processforming a MCF component 10. A draw tower for making multicore opticalfiber includes a furnace 72 for heating a glass preform 71 having amulticore fiber construction, a diameter monitor 73, and a coolingsystem 74 for cooling an uncoated multicore fiber 75 from a high furnacetemperature to a lower temperature to allow application of, for example,UV curable acrylate coatings to protect the glass fiber from damage.Once the uncoated multicore fiber 75, containing core elements 14, 15,16, 17 surrounded by clad 11 is cooled, coating system 12 is applied bya coating system 77 a, and is cured by exposure to appropriate energy,for example, respective UV light sources. Coating system 77 a comprisestwo stages, a first stage applying primary coating 12 a followed bycuring, and a second stage applying secondary coating 12 b followed bycuring, thereby defining coating system 12. In exemplary embodiments,both coatings comprise a UV curable acrylate mixture of monomers,oligomers, photoinitiators, and additives, and the mixtures are cured atrespective curing stations. One such exemplary curing station 78 a isshown in FIG. 3. Relevant exemplary diameters for MCF component 10include: cladding 11 at 125 μm, primary coating 12 a at 190 μm, andsecondary coating 12 b at 245 μm which is the diameter of the coatedmulticore fiber such as MCF component 10. Optionally, where extradiameter sizes are desired, the manufacturing line can include equipmentapplying a translucent or transparent coating portion 21 with a coatingsystem 77 b which is cured by a single stage UV light station 78 b. Thecoated multicore optical fiber is pulled by tractor 80 in the generaldirection of arrow 81. An optical fiber spin device 79 can be locatedbelow the coating curing unit 78 b. The fiber spin device has rotationalelements engaging the fiber to allow twisting of the optical fiber backand forth.

Detection of core elements 14, 15, 16, 17 is accomplished by monitoringtheir positions prior to applying the acrylate coatings to the multicoreoptical fiber. More specifically, prior to application of the coatings,an imaging and control system 76, 76 a, 76 b provides an energy beamsource 76 emitting an energy beam of a wavelength “W”. The beam impingeson uncoated multicore fiber 75 and the beam is imaged by imaging device76 a, the output thereof is sent to controller 76 b which outputs acontrol signal to fiber spin device 79 and an applicator 36 as shown anddescribed with reference to FIG. 4. Controller 76 b is operative tocontrol applicator 36 for control of application of the colored portion18. Fiber rotational alignment is accomplished by fiber spin device 79as described above which, rather than imparting a random twist, isdriven by controller 76 b to control angular alignment of the multicoreoptical fiber.

Colored portion 18 can be applied in a variety of locations to allow forvariations in desired shapes and radial positions relative to the coreelements. To further illustrate, colored portion 18, as described withreference to applicator 36 (FIG. 4), can be applied in various stationsalong the manufacturing line 70 (FIG. 3) and still be controlled bycontroller 76 b. In other words, applicator 36 can apply the materialcomprising the first reference material, for example, colored portion18, onto a wet secondary coating 12 b at position 82 a between coatingsystem 77 a and curing station 78 a, onto a cured secondary coating 12 bat position 82 b between curing station 78 a and coating system 77 b, orby co-extrusion with secondary coating 12 b. Completion of the foregoingaddition of colored portion 18 produces a MCF component 10 (FIG. 1).

Manufacturing considerations play a role in electing whether to run MCFcomponent 10 to stock on a reel and adding a coating 21 and coloredportion 22 with a separate process (FIG. 4), or to optionally addcoating 21 and with a second reference for example a colored portion 22with respect to the additional thickness process described above (FIG.3). For example, in the optional process, colored portion 22 can beadded to MCF component 10 by locating applicator 36 so that it appliesthe reference section onto a wet secondary coating comprising coating 21at position 82 c (FIG. 3) between coating system 77 b and curing station78 b, or onto a cured secondary coating comprising coating 21 atposition 82 d after curing station 78 b. Combinations of the foregoingcan be implemented as well, for example, where multiple applicators 36are used in selected positions 82 a-82 d respectively.

As to detection and tracking of core elements 14, 15, 16, 17 in theprocess described above (FIG. 3), a first method involves the detectionof the partial or complete absence of light by detector 76 a. Forexample, light at wavelength(s) W impinges onto uncoated fiber 75 andcan pass or be absorbed by the germanium dopant which is part of thecore elements. The measurement by detector 76 a can be done by opticalimaging of a wavelength(s) of light that is highly absorbed by thegermanium, causing a shadow or absence of such wavelength(s). Withreference to FIG. 7, which shows transmission percent (axis Y) as afunction of wavelength W measured in nanometers (axis X), germaniumdoped glass has a strong absorption of light at wavelengths shorter thanapproximately 270 nm as shown by curve C1. By comparison, strongabsorption in silica glass SiO2 starts at significantly shorterwavelengths as shown by curve C2 (reference for example Applied OpticsVol. 23, No. 24, 15 Dec. 1984), in other words, the silica absorptionbecomes appreciable at wavelengths shorter than approximately 180 nm.Zone S, generally disposed between wavelength W1 of about 180 nm andwavelength W2 of about 270 nm, represents an exemplary spectral regionfor detecting Germania doped optical core elements disposed in atransparent cladding of uncoated multicore fiber 75.

Thus, shadowing measurements by the imaging control system 76, 76 a, 76b of the shadowing effects of the germania-doped cores 14, 15, 16, 17embedded within the silica cladding 11 are in generally in zone S atwavelengths W1, W2 of between about 180 nm and 270 nm respectively. Thetransmittance, as a function of wavelength band W1, W2, and asassociated with zone S, is in a range of about 80-90%. However, othertransmissivities can be attained by adjusting the wavelength(s) used,for example, comprising a zone R (FIG. 7), having a wavelength of aboutW1 and a relatively higher wavelength of about 300 nm resulting in atransmittance range of about 70-80% through uncoated multicore fiber 75.Thus a minimum wavelength W1 of about 180 nm can be employed withembodiments of the present disclosure. A number of commerciallyavailable light sources 76 are available in the exemplary wavelengthrange W1, W2, including lasers at 266, 257 and 244 nm. Non-laser lightsources are also available, for example, which operate (at leastpartially) in the W1, W2 region include Deuterium bulb (190-400 nm),Xenon (220-visible), and LED 240 nm, and available from Ocean OpticsInc.

At relatively short wavelengths, the germanium-doped cores can be causedto fluoresce and then be detected by imaging system 76, 76 a, 76 b. Thisis possible as germanium-doped optical fibers and preforms can fluoresceat wavelength(s) W near 420 nm when excited by UV radiation at awavelength below 350 nm, as discussed in “Ultraviolet-excitedfluorescence in optical fibers and preforms”, Herman M. Presby, AppliedOptics, Vol. 20, Issue 4, pp. 701-706 (1981). Both the absorption andfluorescence methods described above use ultraviolet light that will belargely absorbed by conventional fiber optic coatings so it is best todo these two measurements without any coatings in the optical path.

Thus light source 76, detector 76 a, and controller 76 b, operating asan imaging system, are to be adjusted to detect and react to the lightabsorption or fluorescent characteristics of the dopant associated withthe optical core elements, as in this exemplary embodiment, thegermanium dopant. As another alternative, light can be transmittedlaterally through the uncoated fiber 75 and the index of refractiondifferences can be detected, again, through interferometry orcommercially available imaging techniques. In all of the methods, acharacteristic absorption band, for example, between wavelengths W1, W2is to be programmed into and detected by the imaging system 76, 76 a, 76b through uncoated multicore fiber 75.

To further illustrate, FIGS. 5 and 6 illustrate exemplary core elementmeasurement orientations at a position after cooling station 74 (FIG.3). FIG. 5 depicts light source 76 directing an energy beam such aslight beam “W” comprising one or more detection wavelength(s) based onthe known or characteristic absorption band, for example zones S and R,with wavelength boundaries W1,W2 based on the relevant dopant of coreelements 14, 15, 16, 17, for example, germanium, and cladding 11 (FIG.7). Beam W transits cladding 11 between, for example, one or more rowsof core elements 14, 15, 16, 17 and shadowing of the detectionwavelength(s) is detected by detector 76 a (FIG. 5). For example,detection of the maximum amplitude of detection wavelength of beam Wreceived by detector 76 a, as the rotation of uncoated fiber 75 variesby control of fiber spin device 79, indicates that beam W is generallyparallel to the at least one row of core elements 14,15,16,17, as is thecase with line L1 (FIGS. 1-2). On the other hand, FIG. 6 depicts source76 directing beam W toward outer cladding 11, but the detectionwavelength(s) W largely impinges upon, and is partially or whollyabsorbed by, the dopant of core elements 14, 15, 16, 17. Consequently,the detection wavelength(s) W may not be detected by detector 76 a, oris otherwise at a minimum amplitude in the imaging system, as rotationof the uncoated fiber 75 varies, indicating that beam W is generallyperpendicular to the at least one row of core elements, as is the casewhen the beam is essentially parallel to line L2 (FIG. 10).

Detector 76 a will output the imaging information in either exemplarycase (FIGS. 5 and 6) to controller 76 b. Controller 76 b contains aprogrammable device such as a computer or microprocessor, and it will beprogrammed to, as one output control signal, adjust fiber spin device 79to control the orientation of the multifiber fiber core with respect tothe core element position as imaged, for example, as by rotation of themultifiber core to allow maximum detection wavelength values to impingeon detector 76 a. In other words, in the example shown in FIG. 5,controller 76 b will control fiber spin device 79 so that the coreelements 14, 15, 16, 17 will be essentially parallel to beam W and lineL2 whereby colored portion 18 will be applied by applicator 36 to thetop of the multicore fiber (FIGS. 1, 2, and 10). Alternatively, asmentioned above, applicator 36 can be integrated into coloring die 77 a,being a co-extrusion die, thereby co-extruding colored portion 18 withsecondary coating 12 b. Colored portion 18 can be coextruded comprisinga stripe of UV curable ink material(s) of essentially the same thicknessas coating system 12. In addition, applicator 36 can be mounted to bemoved to different axial or radial locations relative to MCF component10. Multiple applicators 36 can be used so that, rather than a singleline or dashed stripe being formed, a radial ring of ink can be appliedto coating system 12 and combinations thereof. Moreover, the multicorefiber can have a series of stripes, dashes, rings, or a series of ringsand stripes on its outer surface of various or similar colors andcombinations thereof

As discussed above, MCF component 10 may be made on draw line 70,reeled, and sent to inventory in the factory. However, to furtherillustrate and describe the alternative process which takes as an inputa MCF component 10 and produces a marked MCF 20, reference is made toFIG. 4 which depicts an exemplary manufacturing process including amarking line 30. Marking line 30 is moving product generally in thedirection of arrow “A”. Marking line 30 contains a scanning camerasystem 31, 32 detecting energy such as visible wavelength light whichlight is reflecting from the surface of MCF component 10. Camera system31, 32 thus detects colored portion 18 on the surface of MCF component10. This information is transmitted to controller 34 for tracking theorientation of the core elements in MCF component 10. Exemplarycontroller, scanning cameras, and applicators are disclosed in U.S. Pat.Nos. 6,293,081, 5,904,037, and 5,729,966 of Corning Cable Systems whichare relied upon and incorporated by reference herein.

To further explain the process, a caterpuller is a traction device withmoving belts, having potentially variable speeds, arranged tofrictionally engage an elongate article such as a fiber, cable, or cablecomponents, and to draw or force the article in a generally rectilineardirection, for example, drawing an article off of a reel and propellingit toward an extrusion die. With reference to FIG. 4, a caterpuller 33contains upper and lower drive belts 33 a and 33 b respectively. Upperdrive belt 33 a has a rotational drive that moves MCF component 10through the process, and lower drive belt 33 b has a lateral drive whichcauses MCF component 10 to roll or twist between belts 33 a, 33 b.Controller 34 adjusts the dispositions of caterpuller 33 based on inputsfrom detectors 31,32 such that the orientation of MCF component 10,based on detection of colored portion 18, is established and maintainedin relation to core elements 14, 15, 16, 17. As such, MCF component 10passes through a coloring die 35 that applies a UV curable layerdefining coating portion 21, for example, which can be translucent,transparent, or of a first color such as white, red, or orange. At leastone applicator 36 applies a second material to coating portion 21 in theform of a stripe, dashed line, or combination thereof defining coloredportion 22, which is to be visually distinct from coating portion 21,and thus portion 22 can be a second color for example, black or blue.The coating portion 21 and colored portion 22 are cured by a UV-lightsource 37 to produce a marked MCF 20. Colored portion 22 defines areference section for an operator's connector termination purposes, and,in this embodiment, the colored portion comprises a color that is, to anoperator's observation, visually distinct from coating portion 21.

In further exemplary embodiments, one or more marked MCF 20 can beconstrained relative to a further layer of material such as an opticalfiber ribbon matrix (FIG. 8) or a tight buffered cable jacket (FIG. 10).In such a case, an optional reference section can be added comprising agroove, dent, or colored portion, such as colored portion 52 (FIG. 8)and colored portion 23 a (FIG. 10), and which colored portion in eachcase is generally aligned with a respective colored portion 22.

More specifically, groupings of MCFs 20 can be formed as a first examplein the form of ribbon cable 50 (FIG. 8) with marked MCFs 20 alignedwithin the ribbon. Marked MCFs 20 are bonded together with a matrixmaterial 51, for example, a UV-light curable acrylate matrix. Coloredportions 22 of each marked MCF 20 in optical fiber ribbon 50 can begenerally aligned, for example, toward the same direction or side of theribbon, such as toward the side of colored portion 52. Alternatively,the colored portions 22 can be aligned in different directions withinthe same optical ribbon, for example, MCFs 20 that are to be utilized byan operator as transmit data (Tx) can be aligned toward one side of theoptical fiber ribbon, and MCFs 20 that are to be utilized by an operatorto receive data (Rx) can be aligned toward a different direction.Alignment variations, for example, can be set according to an angle a ofabout 45 from line L1 or L2 (FIG. 8).

Optical fiber ribbon 50 can be connectorized with multi-fiberconnectors, for example, commercially available push on MPO or MTP®fiber optic connectors. As an alternative to FIG. 8, optical coreelements can be arranged in a column format so that the optical coreelements are generally aligned with line L2 rather than line L1. Anentire column of fiber will enable each fiber to be connected in thesame orientation to transceivers on both the proximal and distal sidesof the fiber ribbon. On a row by row basis, such as an optical ribbon50, a twist of the ribbon will arrange the optical fiber cores, and fora multicore fiber having columns and rows of optical core elements, ashuffle with a left to right mirror image transposition arrangement ofthe cores would maintain the optical core elements on the correctorientation at both ends.

FIG. 9 shows an exemplary optical fiber ribbon manufacturing line 60moving product generally in direction “B” with marked MCFs 20 havingcolored portions 22 generally aligned. This means the colored portionsare within 0-45 degrees of each other relative to the top center of theoptical fiber as angle a illustrates in FIG. 8. Process 60 has a seriesof fiber pay-off assemblies 61, for example, four to six assemblies 61,each supplying the aligned MCFs 20 into a coating die 66 which coats themarked MCFs 20 with matrix material 51. The number of fiber pay-offassemblies 61 is determined by the number of marked MCFs 20 desired forthe optical ribbon 50 being manufactured. For example, a 4-fiber ribbonwould have four pay-offs 61, and a 12-fiber ribbon would have twelvepay-offs 61. Pay-off assemblies 61 each comprise a reel assembly thatallows its marked MCF 20 to pay off under controlled tension. Scanningcameras 64 are positioned to observe marked MCFs 20 to determine theorientation of the colored section 22 and provide a feedback controlsignal 65 to a drive motor 63 that rotates the respective reelassemblies 62 to control the orientation of MCFs 20. Matrix material 51is in turn cured by a UV-light source 67 to produce optical fiber ribbon50 with MCFs 20 having colored portions 22, which as described above,can be aligned according to the same or different angles.

As described above, one or more marked MCF 20s can be constrainedrelative to a further layer of material such as a tight buffered cablejacket (FIG. 10). In such a case, an optional reference section can beadded comprising a groove, dent, or colored portion, such as coloredportion 23 a (FIG. 10). Similar to the process of making optical fiberribbon 50, scanning cameras can be used to detect colored portion 22 andthen an extrusion die would extrude a tight buffered cable jacket ontocoating portion 21, and another applicator 36 would apply the coloredportion 23 a.

The foregoing embodiments allow for a single transceiver design to beused on both ends of marked MCF 20, and it also allows operatorsassembling the parts to use the same termination procedure on either endof marked MCF 20. For example, a proximal transceiver (not shown) mayhave two transmit ports T1 and T2 and two receive ports R1 and R2. Asviewed from the end of the transceiver, the ports would be arranged fromleft to right for example as T1, T2, R2, R1 (FIG. 11). The outer twoports T1, R1 define a two-way communication channel 1 and the inner twoports T2, R2 define a two-way communication channel 2. Marked MCF 20with colored portion 22 positioned up in the proximate transceiver wouldplace core element 14 in communication with a transmitter T1, coreelement 15 in communication with transmitter T2, core element 16 incommunication with receiver R2, and core element 17 in communicationwith receiver R1. The distal end of the multicore fiber would be placedinto the distal transceiver in the same orientation with colored portion22 oriented in an up position which would align core element 14 withreceiver R1 and core element 17 with transmitter T1. Thus the signalfrom transmitter T1 in the proximal transceiver will go to receiver R1in the distal transceiver via core element 14. Likewise, the signal fromtransmitter T1 in the distal transceiver will go to receiver R1 in theproximal transceiver over core element 17. When attaching a connector tomarked MCF 20, the connector is assembled with colored portion 22 towardthe top of the connector on both ends of the fiber, which will ensurethat the cores 14, 15, 16, 17 are aligned with the correct ports.

To further illustrate, reference line L2 is on a line of symmetry ofmarked MCF 20 that does not intersect any core elements, and opticalcore elements on the left hand side of line L2 (FIG. 10) of marked MCF20, for example core elements 14 and 15, have essentially acorresponding mirror image of core elements on the right side of lineL2, for example, core elements 16 and 17. In an exemplary embodiment,when the cable is in a loop of a 180 degree bend, as in a factorytermination procedure, and as shown in FIG. 11, core elements 14 and 15define a pair of corresponding core elements and core elements 16 and 17also define a pair of corresponding core elements. Core elements 14 and15 are above line L2 and are disposed for optical communication withtransmitters at the proximal end of the cable “P”. At a distal end ofthe cable “D”, core elements 14, 15 are below line L2 for opticalcommunication with receivers. Similarly, core elements 16 and 17 aredisposed at distal end D of marked MCF 20 above line L2 for opticalcommunication with transmitters, and they are below line L2 for opticalcommunication with receivers at the proximal end P of marked MCF 20. Inother words, each core element 14, 15, 16, 17 is to be connected at eachend P and D, for example, to respective optical connectors, which are inturn associated with transceivers. To accomplish the correct connectionson both sides, for example, the same transceiver design can be used onboth ends, and the operator is to make sure the at least one coloredportion 22 is positioned indicating alignment of the optical elementswith the optical connector. The relative positions of the transmitterand receiver do not need to be inverted thus simplifying the design anddeployment of the transceivers. For example, colored portion 22 alignedwith line L2 is at the top at both ends of the fiber/cable and is to bealigned with a connector for termination.

As a further illustration, Marked MCF 20 can interface with connectorportions 25 a, 25 b having respective angled polished ends 20 a, 20 b asshown in FIG. 12. Angular polished ends 20 a, 20 b are oriented relativeto cores 14, 15, 16, 17 in a way that the polished ends can be arrangedfor connection on either end P, D with devices such as connectors, amid-span connector 26, or transceivers. Line L2 is generally in theplane of the angularly polished surfaces 20 a, 20 b, and line L1 isaligned with the optical core elements 14, 15, 16, 17 and transits theangled polish plane but is generally transverse to the plane of theangled polish. Line L1 will form an angle relative to the angularlypolished surface generally equal to the angle of the polish. The polishangle being, for example, an angle of about 8-9 degrees relative to lineL1. Both ends P, D of marked MCF 20 can be prepared by the process offlock polishing. An exemplary flock polishing technique is described inU.S. Pat. No. 6,106,368 of Corning Cables Systems which is relied uponand incorporated herein by reference. For orientation of matingconnector parts, the optical connector includes a key 27 (FIG. 13). Inan exemplary embodiment, colored portion 22 is aligned with key 27 alongthe same axis, and line L2 is generally aligned with key 27 as well. Thedisposition of key 27 is at an angle β relative to the optical coreelements and line L1 (FIG. 13), and angle β can be in the range of about45 degrees to about 90 degrees. Colored portion 18 can be aligned withcolored portion 22 (FIG. 10) or radially offset therefrom (FIG. 2). Bothends of marked MCF 20 can be attached to a respective fiber opticconnecter, as described above, defining a jumper cable assembly, or onlyone end can be attached to a connector thereby defining a pigtail cableassembly. As described above, colored portions 18 and 22 can be in thenon-aligned positions with respect to each other (FIG. 2) and duringconnectorization. In alternative embodiments, colored portion 22 will beon a first side of the proximal termination side, and on the opposingside of the distal termination side, and with colored portion 18 on thetop in (FIG. 12), and coating 21 should be transparent or translucent sothat colored portion 18 is observable therethrough.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the embodiments describedherein without departing from the spirit and scope of the claimedsubject matter. Thus it is intended that the specification cover themodifications and variations of the various embodiments described hereinprovided such modification and variations come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method of manufacturing a multicore opticalfiber having at least one colored portion thereon comprising the stepsof: a) translating a multicore optical fiber between an energy sourceand a detector; b) directing a beam of the energy source so that thebeam at least partially impinges upon the multicore optical fiber andcausing an image of the intersection of the beam and the multicoreoptical fiber to be detected by the detector and the detector sending anoutput signal relating to the image to a controller; c) the controllerdetermining the orientation of at least some of the core elements in themulticore optical fiber, and providing a control signal output to atraction device engaging the multicore optical fiber, controlling thetraction device and dynamically adjusting the orientation of themulticore optical fiber in relation to its optical core elements and acoating die; d) passing the multicore optical fiber through the coatingdie; e) the coating die applying a curable layer to the multicoreoptical fiber and thereby defining a coating portion; and f) applying amaterial adjacent the coating portion in the form of a colored portionbeing visually distinct from the coating portion.
 2. The method of claim1, the step of detecting the image of at least some of the core elementsincluding at least partial absorption of the energy by at least onedopant and one cladding.
 3. The method of claim 2, the step of partialenergy absorption being at least partially caused by a germanium dopant.4. The method of claim 2, the step of energy absorption causingfluorescence and the step of determining the orientation of at leastsome of the core elements comprising imaging of the fluorescence.
 5. Themethod of claim 3, the step of energy absorption causing index ofrefraction differences and the step of detection of the image comprisinginterferometry.
 6. The method of claim 1, the step of determining theorientation of at least some of the core elements in the multicoreoptical fiber including programming at least one characteristicabsorption wavelength band of about of between about 180 nm and 270 nmin an imaging system comprising the controller.
 7. The method of claim1, the step of applying a material adjacent the coating portioncomprising a colored portion being visually distinct from the coatingportion and including one of co-extruding the colored portion and ofapplying an ink to the outer surface of the coating portion, andcombinations thereof.
 8. The method of claim 7, the step of applying thecolored portion comprising one of forming the portion with one or morestripes, dashes, rings, or a series of rings and stripes thereon, andcombinations thereof.
 9. A method of making a fiber optic ribboncomprising: a) translating at least two multicore optical fibers madeaccording to the method of claim 1; b) aligning the colored portionsrespectively of the multicore optical fibers; and c) coating themulticore optical fibers with a curable matrix material and curing thematrix material.
 10. The method of manufacturing a multicore opticalfiber according to claim 1, the step of translating including drawingthe multicore optical fiber from a draw tower.
 11. The method ofmanufacturing a multicore optical fiber according to claim 10, the stepof coating the multicore optical fiber occurring after cooling of themulticore optical fiber.
 12. The method of manufacturing a multicoreoptical fiber according to claim 10, the step of determining the coreelement orientation occurring prior to the coating application step. 13.The method of manufacturing a multicore optical fiber according to claim10, the steps of applying the colored portion comprises one of: a)directly applying the colored portion adjacent to the coating after thecoating step but before a curing step of the coating; b) directlyapplying the colored portion adjacent to the coating after a curing stepof the coating; c) and combinations of steps a) and b).
 14. The methodof claim 1, the step of determining the orientation of at least some ofthe core elements in the multicore optical fiber including programmingat least one characteristic absorption wavelength band with a minimumvalue of about 180 nm.
 15. A fiber optic assembly comprising at leastone marked multicore optical fiber, comprising: (a) the marked multicoreoptical fiber comprising optical core elements, the optical coreelements defining an array of at least two optical core elementscontained within a common outer cladding, the common outer claddingbeing at least partially surrounded by a coating layer disposedexternally of the cladding, and the optical core elements being alignedgenerally along a first reference line and being capable of transmittingdata; (b) the multicore optical fiber further comprising proximal anddistal ends thereof, and at least one reference section adjacent to thecoating layer, the reference section is aligned with a second referenceline; (c) the first and second reference lines defining a radial angleabout a center of the multicore optical fiber, the optical core elementsare generally arranged in a column of optical core elements, the columnof optical core elements is aligned with the reference section, and eachoptical core element is arranged to be respectively connected in thesame orientation to transceivers on both the proximal and distal ends.16. The fiber optic assembly of claim 15, the assembly comprising atleast two groups of multicore optical fibers comprising columns and rowsof optical core elements, the assembly further comprising a shuffle witha left to right mirror image transposition arrangement of the coreswhereby the optical core elements are aligned with the reference sectionand each optical core element is arranged to be respectively connectedin the same orientation to transceivers on both the proximal and distalends.
 17. A fiber optic system comprising at least one marked multicoreoptical fiber having proximal and distal ends, and respectivetransceivers optically terminated with the proximal and distal ends, thefiber optic system comprising: (a) optical core elements defining anarray of at least two optical core elements contained within a commonouter cladding, the common outer cladding being at least partiallysurrounded by a coating layer disposed externally of the cladding, andthe optical core elements being aligned generally along a firstreference line and being capable of transmitting data; (b) at least onereference section adjacent to the coating layer, the reference sectionis aligned with a second reference line; (c) transceivers respectivelyterminated with the proximal and distal ends defining a proximaltransceiver and a distal transceiver, each transceiver comprising atleast two transmit ports and at least two receive ports, the ports andrespective optical core elements arranged such that the outer two portsdefine a first two-way communication channel, and the inner two portsdefine a second two-way communication channel; and (d) the proximal anddistal transceivers are in the same orientation with the referencesection oriented in the same position with respect thereto therebyaligning the optical core elements with respective transmitter andreceivers of the transceivers.
 18. The fiber optic system of claim 17,wherein the system comprises respective fiber optic connectors, each ofthe fiber optic connectors including a reference structure for alignmentwith each of the proximal and distal transceivers and the multicoreoptical fiber, and each the fiber optic connector is assembled to therespective transceivers with the reference section aligned toward thereference structure of the connector on both ends of the fiber multicorefiber thereby aligning the ports and the optical core elements.
 19. Afiber optic assembly comprising at least one marked multicore opticalfiber having at least one end with an angled surface area, the markedmulticore optical fiber further comprising: (a) optical core elements,the optical core elements defining an array of at least two optical coreelements contained within a common outer cladding, the common outercladding being at least partially surrounded by a coating layer disposedexternally of the cladding, and the optical core elements being alignedgenerally along a first reference line and being capable of transmittingdata; (b) two ends defining proximal and distal ends thereof, and atleast one reference section adjacent to the coating layer, the referencesection is aligned with a second reference line; (c) the first andsecond reference lines defining a radial angle about the center of themulticore optical fiber, and each optical core element is arranged to berespectively connected to optical devices; (d) an angled surface areacomprising an orientation relative to the optical core elements and thereference section, and the angled surface area interfaces with at leastone of the optical devices, the first reference line is generallytransverse to the angled surface area and forms an angle relative to theangled surface area, and the second reference line is generallytransversely disposed along the angled surface area and is aligned withthe reference section; and (e) the reference section is aligned with atleast one other optical device with the reference section oriented inthe same position with respect to such other device thereby aligning theoptical core elements with the optical devices.